See how your 401(k) contribution changes your taxes and paycheck
A Traditional 401(k) contribution can reduce the federal income tax you pay today. But how much will your paycheck actually decrease, and how does that compare with putting the same amount into a Roth 401(k)?
Enter your salary, filing status, contribution amount and employer-match details. This calculator estimates your 2026 federal tax reduction, optional state income-tax savings, take-home-pay impact, available contribution room and money going into your retirement account.
Calculate your Traditional vs. Roth 401(k) tax savings
This tool compares a full-year estimate with and without your new 401(k) contribution. It does not assume every dollar saves tax at a single fixed bracket rate.
2026 standard deduction: $16,100 for single filers.
This is a simple state marginal-rate assumption, not a complete state tax calculation. Pennsylvania, for example, generally taxes employee Traditional 401(k) contributions rather than excluding them from PA compensation.
Matching formulas are employer-specific. Enter the details from your plan document or benefits portal.
Zero matching rate is the default because your employer’s plan has not been verified. Match eligibility, eligible compensation, true-up rules, vesting and contribution timing can change the actual amount.
All entries are processed in your browser. The tool does not request your Social Security number, plan login, employer account or investment details.
How much tax can a Traditional 401(k) save you in 2026?
Traditional 401(k) salary deferrals generally reduce your federal taxable wages for the year. The current income-tax savings depend on the amount contributed and how your contribution reduces taxable income across federal tax brackets.
For a more accurate estimate, the calculator compares your projected income tax before and after the contribution. This matters if the contribution crosses a bracket boundary or if nonrefundable credits reduce the income tax you actually owe.
Traditional 401(k)
Eligible contributions generally reduce current federal income-tax liability. The money is generally taxed when distributed later, subject to applicable retirement account rules.
Roth 401(k)
Contributions are generally made with after-tax wages, so there is usually no current-year income-tax reduction. Qualifying future distributions can be tax-free.
Employer match
Employer contributions can increase your retirement account balance without an equal additional deduction from your take-home pay. The actual amount depends on your plan formula.
Example: $85,000 salary with an $8,500 Traditional 401(k) contribution
Consider a single employee earning $85,000 in 2026, taking the $16,100 federal standard deduction and contributing $8,500 to a Traditional 401(k). Assume no other taxable income, deductions or credits.
| Calculation | Without new 401(k) | With $8,500 Traditional contribution |
|---|---|---|
| Gross wages before 401(k) | $85,000 | $85,000 |
| Traditional employee contribution | $0 | $8,500 |
| Federal income wages after contribution | $85,000 | $76,500 |
| Federal standard deduction | $16,100 | $16,100 |
| Estimated federal taxable income | $68,900 | $60,400 |
| Estimated federal income tax | $9,870 | $8,000 |
| Federal income-tax saving | — | $1,870 |
Federal tax savings
$1,870 annually. The $8,500 contribution reduces income taxed at the 22% federal marginal bracket in this particular example.
Paycheck impact
$6,630 annual cash reduction after the modeled federal savings, or approximately $255 per biweekly paycheck. State savings and employer match are excluded.
This example explains why an $8,500 Traditional 401(k) deferral does not necessarily reduce net pay by the full $8,500. Some of the contribution is offset by lower current income-tax liability.
Maximum 401(k) employee contributions and catch-up limits
The 2026 employee deferral limit applies to combined eligible Traditional and Roth elective deferrals, generally across participating plans subject to the shared limit. It is not a separate $24,500 limit for each contribution type.
| Participant age by December 31, 2026 | Base deferral | Catch-up | Possible employee maximum |
|---|---|---|---|
| Under age 50 | $24,500 | $0 | $24,500 |
| Age 50–59 | $24,500 | $8,000 | $32,500 |
| Age 60–63 | $24,500 | $11,250 | $35,750 |
| Age 64 or older | $24,500 | $8,000 | $32,500 |
What if you change jobs during 2026?
If you contributed to a 401(k) at one job and started a new job, your standard employee deferral limit generally does not reset just because you switched employers. Track your combined eligible elective deferrals for the year.
For example, if you are under 50, already contributed $10,000 at a previous employer, and have no special exceptions, your remaining standard elective deferral room for 2026 is $14,500.
What does the calculator do if you enter too much?
The tool caps your proposed additional employee deferral to the remaining applicable modeled room, taking account of age and prior 2026 elective deferrals. It also flags when your entries may need plan-specific review.
Actual eligibility may be lower because of compensation, plan design, nondiscrimination testing, payroll availability, employer rules or other retirement plan limitations.
Traditional vs. Roth 401(k): which saves more tax?
Neither is automatically better for every employee. A Traditional 401(k) generally favors current income-tax relief. A Roth 401(k) generally gives up current tax relief in exchange for potentially tax-free qualifying withdrawals later.
| Feature | Traditional 401(k) | Roth 401(k) |
|---|---|---|
| Current federal income-tax reduction | Generally yes, for eligible pretax deferrals | Generally no |
| Current Social Security and Medicare savings | Generally no | Generally no |
| Typical income-tax treatment at withdrawal | Taxable when distributed, unless an exception applies | Qualified distributions are generally tax-free |
| Five-taxable-year Roth qualification rule | Not a Roth qualification requirement | Generally applies to tax-free qualified Roth distributions |
| 2026 employee elective deferral limit | Generally shared across eligible Traditional and Roth elective deferrals | |
| Employer match | May be available under plan terms | May be available under plan terms |
| Best tax comparison | Current tax savings versus future expected tax on withdrawals | Current tax cost versus future qualified tax-free withdrawals |
When Traditional might be attractive
- Your current marginal income-tax rate is relatively high.
- You want to reduce current taxable income and estimated income-tax liability.
- You expect to have a lower effective tax rate when withdrawing retirement funds, although that cannot be guaranteed.
When Roth might be attractive
- Your current income-tax rate is relatively low.
- You want to diversify future taxable and tax-free retirement income sources.
- You expect higher tax rates or substantial taxable income later, while accepting uncertainty about future laws.
Can you contribute to both?
Many employer plans permit a split between Traditional and designated Roth salary deferrals. Both typically count toward the same overall employee elective deferral limit. The calculator’s custom mix field estimates the immediate income-tax effect of that split.
How employer 401(k) matching affects your total savings
An employer match is money your employer contributes to your retirement plan according to its terms. It is not the same as your employee salary deferral and should not be counted as an additional deduction from your paycheck.
Example: 50% match on the first 6% of salary
Suppose your salary is $80,000 and your employer contributes $0.50 for each $1 you defer, up to the first 6% of eligible compensation.
| Employee contribution | Employee annual amount | Illustrative employer match | Total contributions |
|---|---|---|---|
| 3% of salary | $2,400 | $1,200 | $3,600 |
| 6% of salary | $4,800 | $2,400 | $7,200 |
| 10% of salary | $8,000 | $2,400 | $10,400 |
Under this example formula, the maximum employer match is reached once the employee contributes 6% of eligible salary. Additional employee contributions can still build retirement savings, but do not increase this particular match.
For actual details, review your Summary Plan Description, benefits portal or plan administrator’s contribution and matching policy.
How a 401(k) contribution changes weekly, biweekly and monthly take-home pay
For Traditional contributions, the cash reduction is usually smaller than the deferral amount because current income taxes may decrease. For Roth contributions, there is generally no comparable immediate income-tax reduction.
Employee deferral − estimated current federal income-tax savings − eligible estimated state income-tax savings = approximate reduction in take-home cash.
Example: $6,000 Traditional contribution
If the entire $6,000 contribution falls within a federal bracket and is eligible for a flat additional state marginal saving, the following simplified examples apply.
| Federal marginal rate | State rate assumed | Estimated total savings | Cash cost of $6,000 deferral |
|---|---|---|---|
| 12% | 0% | $720 | $5,280 |
| 22% | 0% | $1,320 | $4,680 |
| 22% | 5% | $1,620 | $4,380 |
| 24% | 5% | $1,740 | $4,260 |
These examples are not universal results. Your real savings can vary when your contribution spans multiple income-tax brackets or changes deductions, credits and other eligibility calculations.
Why does my payroll check show a different amount?
Payroll uses actual wages, pay frequency, Form W-4 information, year-to-date deferrals and federal withholding tables. An annual tax calculation cannot reproduce all employer payroll details.
If you need to adjust federal withholding, use the official IRS Tax Withholding Estimator and review your W-4 instead of treating the calculator as an exact paycheck statement.
Does a Traditional 401(k) reduce state income tax?
It depends on the state. Many states generally follow federal exclusions for eligible Traditional 401(k) employee deferrals, but not all states treat those wages in the same way.
States that generally follow pretax treatment
In a conforming state, eligible Traditional 401(k) deferrals may reduce the current state taxable wage base. Use a properly researched marginal rate to estimate the additional benefit.
Pennsylvania exception
Pennsylvania generally does not exclude employee contributions to a Traditional 401(k) from PA taxable compensation. The state income-tax savings from the employee deferral may therefore be zero.
For Pennsylvania’s treatment, review the official Pennsylvania Personal Income Tax Guide — Gross Compensation.
2026 Roth catch-up requirement for higher-paid employees
Beginning in 2026, a Roth catch-up requirement applies to certain catch-up-eligible participants whose prior-calendar-year FICA wages from the employer sponsoring the plan exceeded the indexed threshold.
For 2026, the threshold is more than $150,000 of applicable 2025 wages. When the rule applies, covered catch-up contributions must be made as designated Roth contributions rather than pretax catch-up deferrals.
Under age 50
No ordinary age-based catch-up contribution. The regular 2026 deferral limit applies, subject to plan rules.
Age 50–59 or 64+
Generally eligible for the additional $8,000 catch-up if the plan permits it. Covered higher-earner catch-up dollars may need Roth treatment.
Age 60–63
May qualify for a higher $11,250 catch-up if the plan permits it. The applicable Roth catch-up requirement also needs review.
What if you are not sure whether the rule applies?
Ask payroll or your benefits administrator to confirm the applicable 2025 FICA wages and the plan’s 2026 catch-up procedures. Current-year salary alone is not sufficient to establish the prior-year threshold test.
Read the IRS catch-up contribution guidance for the official rules.
How to set up or increase your 401(k) contributions in 2026
- Open your employer’s benefits or retirement portal. Identify the 401(k) plan administrator, participation eligibility, contribution options and current salary deferral elections.
- Review the plan’s matching formula. Read the Summary Plan Description or contact your benefits team to confirm the employer match, eligible compensation, vesting and any true-up provisions.
- Check your 2026 contribution limit. Use the IRS 401(k) limits page and account for prior contributions at other jobs.
- Determine your Traditional/Roth eligibility. If making catch-up contributions in 2026, check whether the mandatory Roth catch-up rule applies based on your prior-year employer wages.
- Choose the contribution type and amount. Decide on a fixed dollar amount or percentage of eligible pay. Check whether the plan offers Traditional, Roth or a split.
- Submit the payroll election. Follow your plan’s online or employer-provided procedure and check when the change becomes effective. Elective deferrals generally must be made through qualifying payroll arrangements rather than a later personal deposit to the 401(k).
- Verify the next paystub. Compare the retirement deduction, federal taxable wages, income-tax withholding and any employer matching information with the chosen election.
- Recheck after salary or job changes. Track total employee deferrals during the year to avoid excess contributions and ensure the election remains appropriate for your cash flow.
Can the 2026 Saver’s Credit increase your retirement tax benefit?
Eligible lower- and moderate-income taxpayers may qualify for the nonrefundable Retirement Savings Contributions Credit, commonly called the Saver’s Credit, when contributing to an eligible retirement account.
For 2026, the applicable adjusted gross income eligibility ceilings include $40,250 for single filers, $60,375 for heads of household and $80,500 for married couples filing jointly. Other age, student, dependent and contribution requirements apply.
The credit may be 10%, 20% or 50% of eligible contributions up to the applicable contribution amount considered under IRS rules, subject to available tax liability and other limitations.
The newer federal Saver’s Match applies beginning with eligible contributions for 2027, rather than replacing the Saver’s Credit for ordinary qualifying 2026 contributions.
Official resources: IRS Saver’s Credit and IRS Saver’s Match.
Why the 401(k) tax savings on your paycheck may not match this calculator
| Issue | Possible reason | What to check |
|---|---|---|
| Tax savings seem too high | The entered state rate may not apply, tax credits may absorb current tax liability, or income data are incomplete. | State tax rules, actual income and verified credits. |
| Traditional contribution does not reduce Social Security | Employee Traditional 401(k) deferrals generally remain subject to FICA. | W-2 Boxes 1, 3 and 5. |
| Roth contribution does not lower income tax | Roth elective deferrals are generally made with after-tax wages. | Payroll election and designated Roth account details. |
| Employer match is lower than expected | Per-paycheck matching, eligibility, true-up or vesting provisions. | Plan document and employer benefits portal. |
| Maximum contribution seems restricted | Combined employee elective deferral limits, age or earlier deferrals. | Year-to-date deferrals across applicable plans. |
| Catch-up contributions appear as Roth | The 2026 higher-earner Roth catch-up requirement may apply. | 2025 FICA wages with the plan sponsor and administrator guidance. |
| Paycheck reduction differs | Exact payroll withholding uses Form W-4 elections and employer pay-period calculations. | Payroll records and IRS Publication 15-T. |
| State savings seem wrong | State tax conformity, state brackets or special compensation rules differ. | Relevant state revenue agency instructions. |
401(k) Tax Savings Calculator 2026: 10 FAQs
1. How much tax does a Traditional 401(k) contribution save in 2026?
The tax savings depend on your contribution, filing status, taxable income, deductions, credits and applicable state treatment. A $5,000 contribution entirely within the 22% federal bracket could reduce federal income tax by about $1,100, before considering additional factors. The calculator compares federal income tax before and after the contribution.
2. What is the maximum 401(k) contribution for 2026?
The regular employee elective deferral limit is $24,500. If allowed by the plan, employees age 50–59 or 64 and older may generally contribute an additional $8,000, while employees age 60–63 may qualify for an $11,250 higher catch-up. Additional plan, compensation and Roth catch-up requirements may apply.
3. Do Traditional 401(k) contributions lower Social Security and Medicare tax?
Generally no. Employee Traditional 401(k) salary deferrals are typically excluded from current federal income taxable wages but remain subject to Social Security and Medicare taxes. The calculator does not incorrectly apply an additional FICA saving to the contribution.
4. What is the difference between Traditional and Roth 401(k) tax savings?
Eligible Traditional contributions generally reduce federal income tax today. Roth contributions generally do not reduce current income tax, but qualified future Roth distributions may be tax-free if the applicable conditions are met. The better choice depends on current and future tax circumstances.
5. How does a 401(k) contribution affect my biweekly paycheck?
A Traditional deferral reduces the cash paid to you, but a decrease in current income-tax withholding may offset part of that reduction. The calculator estimates annual income-tax savings and divides the corresponding annual take-home reduction by 26 for a biweekly illustration.
6. Does my employer’s 401(k) match reduce my taxes?
Employer matching contributions generally do not create the same current employee income-tax deduction as a Traditional employee salary deferral. They can add to your retirement savings under the plan. The calculator displays the estimated employer match separately from current-year employee income-tax savings.
7. What is the 2026 Roth catch-up rule for higher-paid workers?
For certain catch-up-eligible participants, catch-up contributions must be made on a Roth basis when applicable prior-year FICA wages from the plan sponsor exceeded $150,000 for the 2026 rule. Confirm applicability and payroll implementation with your employer or plan administrator.
8. Can I contribute to both a Traditional and Roth 401(k) in 2026?
Yes, if your employer’s plan permits both contribution types. The combined employee elective deferrals generally count toward the shared annual limit. A custom allocation can provide some current tax reduction through Traditional contributions while allocating other contributions to Roth.
9. Do I get a state income-tax deduction for 401(k) contributions?
State treatment varies. Many states generally follow federal pretax treatment, but Pennsylvania generally includes employee Traditional 401(k) deferrals in PA taxable compensation. Confirm your state’s rules before including state savings in the estimate.
10. Can I claim another federal tax deduction for a Traditional 401(k) on Form 1040?
Eligible Traditional employee salary deferrals are generally excluded from taxable W-2 Box 1 wages rather than separately deducted again on Form 1040. Claiming the same deferral twice would be incorrect. Other retirement-related credits or deductions may have separate eligibility rules.
Official IRS sources for 2026 401(k) tax savings and contribution rules
- IRS 401(k) contribution limits: 2026 employee and employer contribution limits.
- IRS catch-up guidance: Age-based catch-ups and mandatory Roth catch-up rules.
- IRS Topic 424: 401(k) tax treatment and eligible elective deferrals.
- IRS designated Roth accounts: Roth contributions and qualified distribution rules.
- IRS 2026 federal rates: 2026 tax brackets and standard deductions.
- IRS Publication 15-T: Federal payroll withholding methods.
- IRS Saver’s Credit: Eligible retirement savings contribution credit.
- IRS withholding estimator: Check federal W-4 withholding.
- PA Department of Revenue: State treatment of employee retirement deferrals.